1. Field of the Invention
The invention relates to a manufacturing and assembling method for an electronic card comprising an electrically insulating card support provided with a cavity for accommodating an integrated circuit and, on one surface, metal contact pads electrically connected to contacts of said integrated circuit.
The invention also relates to the electronic card obtained by this method.
The integrated circuit (or chip) inserted in the cavity of the support may be an electronic memory or a microprocessor of greater surface area than the simple memory.
2. Discussion of the Related Art
The methods used at present for realising electronic chip cards use a printed circuit which is deposited on a support foil, generally made of epoxy glass, polyimide, or polyester, as described, for example, in European Patent EP 0 201 952 B1 in the name of the present Applicant (PHF 85.533). The use of a moulded grid is also known. The support foil or grid carries the external metal contact pads of the card on one of its surfaces, the other surface serves as a support for the electronic chip which is electrically connected to the external contacts through the foil or grid. The material of the support foil and the material used for moulding the grids are insulating materials so as to insulate the external contacts and the internal connections of the electronic chip from one another electrically.
The assembly of the chip card accordingly comprises the following steps:
gluing of the integrated circuit (the chip) on the internal surface of the foil or` grid, PA1 realisation of electrical connections connecting the chip contacts to external metal contact pads (by means of conductive wires), PA1 protecting the chip and the connections by means of a protective resin. PA1 cutting off the electronic module thus formed so as to detach it from the support foil or grid, PA1 insertion and gluing of the module in a card support of synthetic resin material (usually PVC, ABS, or polycarbonate) in which an accommodation space (cavity) has previously been realised for accommodating said module with its side which supports the integrated circuit (the chip). This cavity may be realised by moulding, injection-moulding, or by spot-facing. PA1 the application of electrical conductor tracks by an MID (Moulded Interconnection Devices) technique, all provided against the bottom and the lateral walls of said cavity and each connected to one of said metal contact pads arranged on the surface of the support which comprises said cavity, PA1 the realisation of electrical connections interconnecting the contacts of the integrated circuit positioned in the cavity and said conductor tracks at the bottom of the cavity, PA1 filling up of said cavity with a protective resin which is subsequently polymerized.
With these methods, the operation of protecting the electronic chip and the connections is often a delicate one because the thickness of this protection must be perfectly controlled for rendering possible the insertion into the cavity of the card support which has a depth of no more than 650 .mu.m.
The insertion of the electronic module into the card is also delicate and demands very narrow tolerances as to the planeness and lateral position so as to avoid practical problems with the use of card readers, or with the accommodation in the cavity.
On the other hand, the gluing of the electronic module must be very effective so as to comply with torsion and bending test requirements.
Finally, these methods necessitate the use of a foil or grid which contribute considerably to the final cost of the product.